1. Field
Embodiments of the present disclosure relate to an image forming apparatus configured to form a color image through a single pass scheme, and a control method thereof.
2. Description of the Related Art
An image forming apparatus using an electro-photographic scheme such as a laser printer and a digital copier may be defined as an apparatus configured to radiate light on a photosensitive medium that is charged with a predetermined electric potential to form an electrostatic latent image on the photosensitive medium. After developing the electrostatic latent image to a visible image by supplying a toner, that is, a developing agent, to the electrostatic latent image, the visible image may be transferred and fixed to a paper, thereby achieving an image printing. A color image forming apparatus of an electro-photographic scheme may be configured to supply the toners having four types of colors, which are black ‘K’ (black), yellow ‘Y’ (Yellow), magenta ‘M’ (Magenta), and cyan ‘C’ (Cyan), to the photosensitive medium to form images having different colors to each other. By overlapping the images, a color image is produced.
At the color image forming apparatus, when the images having different colors to each other are overlapped, if the image of each different color is not overlapped at a correct position, the border portion of the image may appear blurry, and thus the quality of the image may be poor. This may occur as a result of a number of variable factors, such as a replacement of a developer or an increase in the number of prints. Thus, a color registration task, which is configured to align the images that are provided with different colors to each other, so that the images are overlapped at correct positions, is needed.
A color image forming apparatus of a single pass scheme may use four exposure units and four photosensitive drums. When a number of variable factors, such as a replacement of a developer or an increase in the number of prints occurs, the apparatus may be configured to perform an ACR (Auto Color Registration) to automatically perform a color registration. Thus, high-quality color images may be produced.
To enhance the performance of the ACR, in general, a method of increasing the number of ACR patterns is applied. But, when the number of the ACR patterns is increased, the performing time of the ACR may be increased. To increase the number of the ACR patterns, if the patterns are formed in an adjacent manner on the intermediate transfer belt, a possibility of the patterns being detected by a sensor while being mixed with the noise component generated by the scratch or the punching of the intermediate transfer belt may be increased. Thus a prediction of a correction value of the ACR may be less accurate, thereby reducing the performance of the ACR.
With respect to a process of transferring the ACR patterns from the photosensitive drum to the intermediate transfer belt, a periodic change of a linear speed by a rotation of the photosensitive drum generates an (Alternating Current) AC component, and thereby the accurate DC offset value may be difficult to determine.